Dow futures were down about 300 points early Wednesday morning, or about 1.5%. At their low point on Tuesday night, Dow futures were down more than 900 points.

Nervous investors may have been soothed after Trump called for Americans to unite after the brutal election campaign.

"Trump definitely sounded more presidential than he has done at any stage during the election campaign," Kathleen Brooks, a research director at City Index in London, said of his speech. "In fact, one could argue that this outsider has delivered an establishment-style victory speech."

Most European stock markets are declining, but the losses are not huge. Russia was one of the few winners. Its main market index was rising about 1.5% as investors expect Trump and Russian President Vladimir Putin to form a closer relationship.

Stock indexes across Asia closed the day in the red. Japan's Nikkei plummeted 5.4% and the Hang Seng in Hong Kong fell by 2.2%.

Stock futures began tumbling after 9 p.m. ET as it became clear that Hillary Clinton's chances of winning crucial states such as Florida, North Carolina and Ohio werein serious doubt. She would later lose all three to Trump.

"It is looking like another Brexit-type surprise," said Ryan Detrick, senior market strategist at LPL Financial.

The U.K.'s FTSE 100 dropped 3.2% the day after the vote. The British pound had one of its biggest one-day declines on record, falling 9% to $1.33, then the lowest it had been since 1985.

Markets have rebounded since then, partially because the weak pound helped support the economy.

The U.S. dollar hasn't been hit as hard as the pound was -- it dropped sharply but then recovered most of its losses Wednesday morning.

While Wall Street is on track for post-election losses, they are not nearly as bad on a percentage basis as those experienced during the 2008 financial crisis when several plunges of greater than 6% occurred.

"The Mexican economy is most tied to Donald Trump's criticism of global trade. It really is ground zero of this discussion economically," said Nicholas Colas, chief market strategist at brokerage firm ConvergEx.